Mudsaver valve

ABSTRACT

A mudsaver valve for insertion into the upper end of a well casing includes an elongated cylindrical valve body member having a central bore for receiving an elongated generally tubular valve closure member for movement in the body bore between valve closed and open positions. Passages in the closure member open to the outer surface thereof and spaced apart seal members mounted on the closure member prevent fluid flow out of the valve when the closure member is disposed in a closed position in the body. The body supports plural circumferentially spaced spring biased drag blocks or radially deflectable leaf or bow spring members which are engageable with the casing to support the body stationary in the casing so that the closure member may be reciprocated with respect to the body between valve open and closed positions.

FIELD OF THE INVENTION

[0001] The present invention pertains to a mudsaver valve for use inwell drilling and casing installation operations.

BACKGROUND

[0002] In the art of well drilling operations, including operations toinstall well casing, it is common practice to fill the tubular casingwith drill cuttings evacuation fluid, commonly known as drilling fluidor “mud”, and circulate such fluid through the casing and the wellboreduring casing installation procedures, in particular. So-called mudsavervalves are usually connected to the lower end of a hollow drill stemdrive member or Kelly or to the lower end of a circulating head toprevent spillage of the drilling fluid or “mud” when the Kelly orcirculating head are disconnected from the drill stem or casing, as thecase may be.

[0003] The use of a mudsaver valve is desirable to prevent theaforementioned loss of drilling fluid, to prevent unsafe conditions forrig operating personnel and also to minimize contamination of theenvironment in the vicinity of the drilling operation.

[0004] Various types of mudsaver valves have been developed in the priorart. A typical mudsaver valve design is characterized by a poppet typeclosure member which is held against a valve seat by a spring. In manyinstances, solid particulates are distributed throughout the drillingfluid, such as lost circulation material or unseparated drill cuttings,and these particulates become trapped between the valve closure memberand the valve seat resulting in improper closure of the mudsaver valveand the loss of drilling fluid out of the circulating head or conduitswhich supply the fluid during operations.

[0005] Another problem associated with prior art mudsaver valvespertains to the inability to at least reliably and substantiallyequalize the pressure between the casing or drill stem interior passageand the fluid supply conduit to which the mudsaver valve is connected.Fluid pressures in the so-called standpipe or conduit to which themudsaver valve is connected for supplying fluid to the drill stem orcasing should be reduced to substantially the same pressure as the fluidin the drill stem or casing section at the upper end thereof prior todisconnection and withdrawal of the circulating head and mudsaver valvefrom the casing. However, if fluid pressure should increase in thecasing beyond a reasonable value which would permit disconnection of thecirculating head from the casing, this pressure can be monitored bysuitable instruments connected to the fluid supply conduit or standpipewhich is connected to the circulating head. Accordingly, the mudsavervalve should be operable to substantially equalize the fluid pressure inthe drill stem or casing with that in the standpipe or fluid supplyconduit before disconnecting the fluid circulating head or similarcasing installation equipment from the drill stem or casing.

[0006] Still another problem associated with prior art mudsaver valvespertains to the rapid deterioration of the valve components due toerosion caused by high fluid velocities between the closure member andthe valve seat or through flowports which are provided in the closuremember for certain types of mudsaver valve configurations.

[0007] Accordingly, the desiderata in mudsaver valves includes (a)reliable operation in moving the valve closure member between open andclosed positions to assure that there is negligible spillage of drillingfluid onto the drilling rig floor, (b) assurance that pressures in thecasing and the fluid supply conduit are substantially equalized beforethe fluid supply conduit and mudsaver valve are withdrawn from the wellcasing and (c) provision of a valve configuration that minimizes erosionand early failure of the valve working parts. It is to these ends thatthe present invention has been developed.

SUMMARY OF THE INVENTION

[0008] The present invention provides an improved mudsaver valve for usein well drilling and casing installation operations.

[0009] In accordance with one important aspect of the present invention,a mudsaver valve is provided which includes an elongated tubular mandreltype closure member which is slidably disposed in a generallycylindrical valve body and is movable between valve open and closedpositions wherein the mandrel moves relative to the body out of a lowerend thereof and substantially clear of any valve seat or seal boreportions of the body which might suffer erosion from high velocity fluidimpinging thereon. In accordance with another aspect of the presentinvention, a sliding mandrel type mudsaver valve is provided whichincludes spaced apart annular seals which seal off flow of fluid out ofthe valve when the closure member is retracted into the bore of thevalve body.

[0010] In accordance with yet another aspect of the invention, amudsaver valve is provided which includes members mounted on the valvebody which frictionally engage the inner borewall of a casing or drillstem section into which the mudsaver valve has been inserted to arrestmovement of the valve body and to allow the valve closure member to moverelative to the valve body between valve open and closed positions. Thesliding mandrel type closure member is movable to a valve open positiononly after it has been inserted into the upper end of a casing sectionand the closure member is movable to a valve closed position before thebody is forcibly removed from frictional engagement with the innerborewall of the drill stem or casing member. In this way, there isassurance that the mudsaver valve will be in a closed position before itis withdrawn from the upper end of the casing or drill stem section.

[0011] In accordance with still a further aspect of the presentinvention, an improved mudsaver valve is provided which includes anarrangement of resiliently deflectable members which frictionally engagethe inner borewall of a casing section to generally hold the valve bodystationary but to also allow the valve body to be moved between aworking position in the casing and a position retracted out of thecasing. Circumferentially spaced spring biased drag blocks orresiliently deflectable leaf or bow type springs may be mounted on thevalve body for frictional engagement with the casing borewall to retainthe valve body within the casing and to allow for movement of the valveclosure member between valve open and closed positions. Elongatedflexible finger indicators may be provided on the valve body to visuallyindicate to operating personnel the position of the valve body in thecasing.

[0012] Those skilled in the art will further appreciate theabove-mentioned features and advantages of the invention together withother important aspects thereof upon reading the detailed descriptionwhich follows in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a side elevation, in somewhat schematic form, of acasing circulating system including a mudsaver valve in accordance withthe present invention;

[0014]FIG. 2 is a longitudinal central section view of the mudsavervalve shown in FIG. 1 partially inserted in the upper end of a wellcasing section;

[0015]FIG. 3 is a detail section view taken generally from the line 3-3of FIG. 2;

[0016]FIG. 4 is a longitudinal central section view of the mudsavervalve shown in FIG. 2 fully inserted within the casing section and inthe valve open position;

[0017]FIG. 5 is a longitudinal central section view of a first alternateembodiment of the mudsaver valve of the present invention shown within acasing section and in the valve open position;

[0018]FIG. 6 is a top plan view of a removable spring finger dragassembly for the mudsaver valve shown in FIG. 5;

[0019]FIG. 7 is a side elevation of the spring finger drag assemblyshown in FIG. 6;

[0020]FIG. 8 is a longitudinal central section view of a secondalternate embodiment of a mudsaver valve in accordance with theinvention, shown in the valve closed position;

[0021]FIG. 9 is a section view showing the valve of FIG. 8 in an openposition;

[0022]FIG. 10 is a side elevation of the drag assembly for the valveshown in FIGS. 8 and 9; and

[0023]FIG. 11 is a bottom plan view of the drag assembly shown in FIG.10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] In the description which follows, like parts are markedthroughout the specification and drawing with the same referencenumerals, respectively. The drawing figures are not necessarily to scaleand certain features may be shown in somewhat schematic form in theinterest of clarity and conciseness.

[0025] Referring to FIG. 1, there is illustrated a portion of a welldrilling rig including an arrangement adapted for circulating drillingfluid into and through drill stem or casing sections, in particular,while inserting such casing sections into a wellbore. FIG. 1 shows theupper end of a conventional well casing section 10 which is adapted tobe supported by suitable slips, not shown, prior to insertion of thecasing section into a wellbore, also not shown. The circulating assemblyincludes a rig swivel assembly 12, a lifting bail 14 adapted to beconnected to the rig traveling block, not shown, and a conventionalcasing elevator assembly 16 connected to the swivel 12. An elongatedfluid conducting conduit 18 is connected to the swivel 12, dependstherefrom and is in communication with a drilling fluid supply conduit20 connected to the swivel in a conventional manner and to a source ofdrilling fluid, such as high pressure pumps, not shown. Conduit 18 isconnected to a generally inverted can shaped seal member 24 of a typeknown in the art. The seal member 24 may be a commercially availableexternal or internal seal, fillup and circulating tool such as anAutoseal tool available from Weatherford or an FC fillup and circulatingtool available from Frank's International.

[0026] A somewhat flexible, thick walled, reinforced hose type conduit26 depends from the casing seal member 24 and is in communication withthe conduit 18 for receiving drilling fluid therefrom. However, conduit26 may in certain operations be connected directly to conduit 18 andseal member 24 omitted. The lower end of conduit 26 is connected to acoupling 27 which is connected to a mandrel member of a mudsaver valvein accordance with the invention, which valve is generally designated bythe numeral 28. Prior to insertion of casing section 10 fully into awellbore, the mudsaver valve 28 is lowered into the casing section 10sufficiently to allow the valve to open, as will be fully understoodfrom reading the description of the valve hereinbelow. When conduit 26is lowered sufficiently to cause valve 28 to be fully inserted in casingsection 10 and the valve caused to open, drilling fluid is pumped intothe casing section or sections to fill same with such fluid.Subsequently conduit 26 and seal 24 are lowered further until the seal24 engages the upper end 10 a of the casing section in a known manner sothat drilling fluid can continue to be pumped from conduit 20 throughconduits 18 and 26 and through the mudsaver valve 28 into and alsothrough the interior of the casing section. When the casing section 10has been lowered into a wellbore to a point just above the floor of thedrilling rig, not shown, pumping of drilling fluid ceases and afterequalization of fluid pressure in the casing section 10 and the conduit26, the seal member 24 and mudsaver valve 28 are moved upwardly andwithdrawn from the interior of the casing section in a known manner. Theprocess described above is repeated, also in a known manner, asadditional casing sections are added to a casing string being insertedinto the aforementioned wellbore.

[0027] Referring now to FIG. 2, the mudsaver valve 28 is shown in aposition wherein it has just entered the upper end 10 a of the casingsection 10 but is not yet completely in its intended working positionfor circulating drilling fluid into the bore 11 of the casing section.The casing section 10 includes an upper collar portion or box 13 formingpart of the upper end 10 a and having internal threads 13 a of largerinside diameter than the casing bore 11. The casing section 10 is ofconventional construction.

[0028] Mudsaver valve 28 includes a generally cylindrical elongatedvalve body 30 having a longitudinal, central cylindrical bore 32extending therethrough between an upper transverse endface 34 and alower transverse endface 36. Cylindrical bore 32 intersects a conicalbore part 38 which opens to the lower endface 36. Valve body 30 is alsoprovided with three circumferentially spaced elongated rectangular crosssection slots 40, see FIG. 3 also, for receiving three circumferentiallyspaced respective so-called drag blocks 42, as shown in FIGS. 2 and 3,which drag blocks project radially outwardly and are operable toforcibly engage the borewall 11 of casing section 10. The section viewof FIG. 2 has been rotated into the plane of the paper to show two ofthe drag blocks 42. Each of the drag blocks 42 is characterized as agenerally rectangular member preferably formed of a urethane compositionand is provided with an axially sloped outer surface portion 43, asshown in FIG. 2. Each of the drag blocks 42 is retained in its slot 40by a suitable threaded fastener 44, FIG. 2, having a head portion 46disposed in a recess 47. The drag blocks 42 are also each provided withspaced apart spring receiving bores 49, as shown in FIG. 2, forreceiving respective coil biasing springs 50 therein. Biasing springs 50are engageable with the valve body 30 and are sleeved over suitableguide pins 52 mounted on the body 30 and projecting radially outwardlytherefrom. Guide pins 52 are slidably disposed in cooperating bores 54formed in the drag blocks 42, as shown, to assist in guiding andcentralizing the blocks so that the blocks may move radially inwardlyand outwardly with respect to a longitudinal central axis 55.Accordingly, the drag blocks 42 are adapted to frictionally engage theborewall 11 as the mudsaver valve 28 is inserted into the upper end ofcasing section 10, and may be urged radially inwardly as the surfaces 43engage the borewall 11 and remain forcibly engaged with the borewall fora purpose to be described further herein.

[0029] Referring further to FIGS. 2 and 3, the mudsaver valve 28includes an elongated, generally cylindrical closure member 60 disposedin bore 32 and suitably secured to a conically shaped guide nose 62disposed on the lower end of the closure member. The closure member 60is provided with an externally threaded upper end part 63 suitablyconnected to an elongated cylindrical tubular mandrel 61, as shown.Mandrel 61 is connected to conduit 26 via coupling 27, see FIGS. 1 and4. The closure member 60 includes a central longitudinal flow passage 65in fluid flow communication with mandrel 61 and extending from the upperend 63 to axially inclined fluid discharge ports 66 which open to theouter cylindrical surface 67 of the closure member between spaced apartannular, elastomer lip type seals 69. The seals 69 are disposed insuitable annular grooves 70 and 72 on the closure member 60 spaced aparton opposite sides of the points at which the ports 66 intersect thesurface 67 of the closure member 60.

[0030] In the position of the mudsaver valve 28 shown in FIG. 2, theclosure member 60 is in a valve closed position and fluid flow out ofthe mudsaver valve is blocked by the position of the closure member 60relative to the valve body 30. There are no substantial resultantpressure fluid forces acting on the closure member 60 tending to bias itin the open position or in the closed position shown, due to theconfiguration of the ports or passages 66 and the arrangement of theseals 72 when the closure member is in the valve closed position.However, when the mudsaver valve 28 is inserted into a casing section,such as the casing section 10, the drag blocks 42 will forcibly engagethe borewall 11 permitting only limited entry of the body 30 past theintersection of the borewall 11 with the enlarged diameter bore whichincludes internal threads 13 a. Continued downward movement of theconduit 26 and the structure connected thereto will cause the closuremember 60 to move downward to the position shown in FIG. 4 wherein theports 66 are open to the interior passage 11 a of the casing section 10.Drilling fluid may then flow down through conduit 26, mandrel 61 andclosure member 60 into casing section 10.

[0031] As shown in FIG. 4, the valve body 30 has entered the casingsection 10 only a relatively short distance below the intersection ofthe bore 11 with the bore formed by the internal threads 13 a of theupper end 10 a of the casing section. Valve body 30 is preferablyprovided with one or more upwardly extending elongated spring steelposition indicator or “telltale” fingers 73, FIG. 4, to indicate whenthe body 30 is sufficiently inserted in casing section 10. Indicatorfingers 73 are suitably connected to the upper end of body 30 adjacentend face 34, as shown in FIG. 2. Accordingly, when it is desired tocirculate drilling fluid through the casing section 10, the mudsavervalve 28 and conduit 26 are inserted in the upper end 10 a and movedownwardly until indicator fingers 73 disappear within the casingsection. Conduit 26 is moved further downward to assure that valve 28has moved to the open position and conduit 26 may also, when fluidcirculation is to commence, be moved downward until the seal 24 extendsover the upper end of the casing section 10 in a known manner. At thistime, the body 30 has only moved a short distance into the casingsection 10, as shown in FIG. 4, but the closure member 60 has extendedto the position shown to allow free flow of drilling fluid through thepassage 65, the ports 66 and into the casing bore.

[0032] When it is desired to withdraw the mudsaver valve 28 from theinterior of the casing section 10, the aforementioned traveling blockraises the swivel 12 and the conduit assembly connected to the mudsavervalve whereby the closure member 60 will move upwardly relative to thebody 30 until flange 62 a of nose 62 engages the lower end face 36 ofthe body and the closure member is fully seated within the body.

[0033] Thanks to the conically tapered bore 38, the seals 69 are guidedinto fluid tight sealing engagement with the body 30 at bore 32 as theclosure member 60 moves into the bore from the valve open position tothe valve closed position shown in FIG. 2. Accordingly, since the body30 is frictionally engaged with the casing section 10 by way of the dragblocks 42, the closure member 60 moves to the valve closed positionbefore the mudsaver valve 28 is withdrawn from the casing and only anegligible amount of drilling fluid may spill out of the upper end ofthe casing section 10 as the circulating assembly shown in FIG. 1 iswithdrawn from the casing section.

[0034] Still further, once circulation of drilling fluid from conduit 20down through conduits 18 and 26 has ceased and while the closure member60 is still in the position shown in FIG. 4, pressures in the casingbore 11 and the conduits of the circulating assembly are essentiallyequalized so that when the seal 24 is moved off of the upper end 10 a ofthe casing section, there is no rapid discharge of pressure fluid fromthe casing. Of course, if rig operating personnel detect substantialpressure in the conduits leading to the casing section 10 prior towithdrawal of the mud circulating assembly from the casing section, theseal 24 and mudsaver valve 28 will not be removed from the casingsection until pressures can be substantially reduced and equalizedbetween the conduit 26 and the casing section 10, for example.

[0035] Referring now to FIG. 5, a first alternate embodiment of amudsaver valve in accordance with the invention is illustrated andgenerally designated by the numeral 128. The mudsaver valve 128 is showninserted within a casing section 10 and includes a closure member 60slidably disposed in a modified valve body 130 and connected to atubular mandrel 161 which is connected to conduit 26 via a coupling 27.Valve body 130 is configured generally like valve body 30 and includes acylindrical longitudinal central bore 132 extending between an upperendface 134 and a lower endface 136. Bore 132 intersects a conical bore138 which opens to the lower end face 136 of the valve body 130 for thesame purpose as the conical bore 38. Valve body 130 includes acylindrical reduced diameter recessed section 135 between the upper endface 134 and the lower end face 136 for supporting a friction or dragassembly, generally designated by the numeral 140.

[0036] The drag assembly 140 includes four, circumferentially spacedlongitudinally extending cantilever spring fingers 142 which are mountedon a hinged collar 144, see FIGS. 6 and 7 also. The collar 144 comprisesopposed arcuate collar members 144 a and 144 b which are hinged togetherat a hinge pin 148. Collar members 144 a and 144 b include spaced apartinterfitting latch members 145 and 147 which are alignable to receive alatch pin 150. Collar members 144 a and 144 b may be latched in a collarclosed position by pin 150 when fitted snugly over the reduced diametersection 135 of body 130. The friction or drag assembly 140 may beselected in accordance with the diameter of the casing bore 11 so thatthe mudsaver valve 128 may be used with various casing sizes andrequiring only that the drag assembly 140 be substituted for a dragassembly having spring fingers of suitable dimensions to provide therequisite resistance to movement through the casing section so as toallow the closure member 60 to move relative to the body 130 in themanner generally as described for the mudsaver valve 28. Moreover, thespring fingers 142 serve as their own telltale or position indicatorsfor determining if the body 130 is sufficiently inserted within thecasing section 10.

[0037] Referring further to FIGS. 6 and 7, the drag assembly 140 isshown with a configuration of the cantilever spring fingers 142 whichproject upwardly and radially outwardly and have somewhat reentrantdistal end parts 143. The spring fingers 142 may be formed of springsteel and are preferably covered or coated with a suitable plasticoverlay, such as a urethane coating 146, to minimize any chance ofdamage to the threads 13 a of the casing section 10 when the mudsavervalve 128 is inserted into the casing. Preferably the body 130 may beinserted only to the extent that the spring fingers 142 forcibly engagethe internal threads 13 a of the casing section and are thus partiallyvisible from the upper end 10 a of the casing section during operationof the mudsaver valve and the circulating assembly.

[0038] In other words, as the mudsaver valve 128 is inserted into acasing section, such as the casing section 10, the valve body 130 isinserted until the upper ends 143 of the spring fingers 142 are visiblejust above the upper end 10 a of the casing section. Then, underoperating conditions using the seal 24, as the seal is lowered andengaged with the upper end of the casing section, the operator of thecirculating assembly is assured that the closure member 60 has moveddownward to the position shown in FIG. 5 relative to the body 130.

[0039] Alternatively, the valve 128 may be inserted to the positionshown in FIG. 5. The mudsaver valve 128 is thus operated insubstantially the same manner as the valve 28 and is easily withdrawnfrom the casing section 10 by merely pulling up on the circulatingassembly, including the swivel 12, until the closure member 60 moves tothe closed position relative to the body 130 and further upward movementresults in the cantilever spring fingers 142 sliding upward infrictional engagement with the casing section so that the valve 128 canbe withdrawn from the casing in its closed position.

[0040] Referring now to FIGS. 8 and 9, a second alternate embodiment ofa mudsaver valve in accordance with the invention is illustrated andgenerally designated by the numeral 228. The mudsaver valve 228 utilizesthe closure member 60 and the mandrel 61 suitably connected to theconduit 26, not shown, by way of the coupling 27. A modified body 230includes a suitable central axial bore 232 for receiving the closuremember 60 in the same manner that the body 30 receives the closuremember 60 of the embodiment of FIGS. 1 through 4. Valve body 230includes central axial bore 232 and a tapered bore portion 238 at thelower end thereof, as illustrated in FIGS. 8 and 9. Accordingly, whenthe closure member 60 moves to a valve closed position, as shown in FIG.8, from a valve open position, as shown in FIG. 9, the seals 69 areoperable to provide fluid tight engagement with the bore 232 in the samemanner as for the embodiments of the mudsaver valve previouslydescribed.

[0041] As shown in FIG. 8, the body 230 includes spaced apartcircumferential flanges 231 and 233 between which is secured a hingedcollar 144 for a modified drag assembly 240. Drag assembly 240 furtherincludes a second hinged collar 144 secured to a generally spool-shapedbody member 245 which includes a central axial bore 246 for receivingthe mandrel 61 in axial sliding engagement therewith. The upper hingedcollar 144 is disposed on the body 245 between opposed circumferentialflanges 245 a and 245 b. The upper and lower hinged collars 144 aresuitably connected to opposite ends of circumferentially spacedelongated spring steel drag members 242, similar to the spring fingerdrag members 142, but secured at their opposite ends to the respectivehinged collars 144 and adapted to retain a somewhat radial outwardprojecting bow shape, as shown. Accordingly, a selected drag assembly240 may be mounted on the mudsaver valve 228, depending on the diameterof casing in which the mudsaver valve is to be inserted, so that thedrag members 242 may engage the bore wall of the casing with sufficientfrictional drag to allow the closure member 60 to move downward out ofthe body 230 sufficiently, as shown in FIG. 9, to uncover the ports 66so that fluid may flow into a casing section, not shown in FIGS. 8 and9, in which the mudsaver valve 228 has been inserted.

[0042] Referring also to FIGS. 10 and 11, further details of the dragassembly 240 are illustrated. Each of the hinged collars 144 is securedin its closed position by pins 148 and 150, as shown, and each of thedrag members 242 may include a suitable elastomer coating 246 formedthereon, such as the aforementioned urethane coating used for the springfingers 142 of the drag assembly 140.

[0043] When the mudsaver valve 228 has been inserted into a casingsection, such as the casing section 10, not shown in FIGS. 8 and 9, thedrag members 242 will engage the casing bore wall sufficiently to allowthe closure member 60 be moved to the position shown in FIG. 9 upondownward movement of the conduit 26, coupling 27 and mandrel 61. Themudsaver valve 228 may be moved to the closed position by pulling up onthe conduit 26, coupling 27 and mandrel 61 until the closure member 60has moved to the position shown in FIG. 8 whereupon the mudsaver valve228 may be withdrawn from a casing section. One advantage of themudsaver valve 228 resides in the arrangement of the drag assembly 240with respect to the coupling 27. As shown in FIG. 9, as the mandrel 61and coupling 27 move downward relative to the body 230, the coupling 27may engage the body 245 to assure that the body and drag assembly 240are fully inserted into the upper end of a casing section. Accordingly,upon withdrawal of the mudsaver valve 228 from a casing section theclosure member 60 will move back into the body 230 before the valve isremoved from the upper end of the casing.

[0044] The construction and operation of the mudsaver valves 28, 128 and228 is believed to be readily understandable to those of ordinary skillin the art based on the foregoing description. Conventional engineeringmethods and materials for mudsaver valves may be used in fabricating thevalves 28, 128 and 228. Although preferred embodiments of a mudsavervalve in accordance with the invention have been described in detailherein, those skilled in the art will also recognize that varioussubstitutions and modifications may be made without departing from thescope and spirit of the invention as recited in the appended claims.

What is claimed is:
 1. A mudsaver valve for use in well operations comprising: an elongated valve body member including an axial cylindrical bore therein; an elongated, generally tubular closure member disposed in said bore in said body member, said closure member including an elongated axially extending passage formed therein and passage means opening to an outer surface of said closure member, said closure member being movable axially in said bore in said body member between valve open and closed positions; and at least one drag member connected to said body member and engageable with a wall of a well conduit upon insertion of said valve into said well conduit for holding said body member substantially stationary with respect to said well conduit to permit opening and closing said valve by moving said closure member axially in said bore of said body member.
 2. The valve set forth in claim 1 including: spaced apart seals on one of said body member and said closure member for preventing flow of fluid from said passage means in said closure member in the valve closed position of said closure member.
 3. The valve set forth in claim 2 wherein: said seals comprise annular seal members mounted on said closure member and engageable with a borewall of said bore in said body member.
 4. The valve set forth in claim 3 including: a tapered bore part extending from one end of said body member and intersecting said bore in said body member for engaging said seals when said closure member moves from a valve open position to a valve closed position.
 5. The valve set forth in claim 1 wherein: said closure member is connected at one end to an elongated conduit for conducting fluid to said passage in said closure member from a source of said fluid.
 6. The valve set forth in claim 1 including: a tapered guide member disposed on one end of said closure member for guiding said valve into said well conduit.
 7. The valve set forth in claim 1 wherein: said drag member comprises plural circumferentially spaced drag blocks mounted on said body member for limited movement relative to said body member and operable to engage a wall of said well conduit.
 8. The valve set forth in claim 7 including: resilient biasing means for yieldably biasing said drag blocks radially outwardly into forcible engagement with said wall.
 9. The valve set forth in claim 8 wherein: said resilient biasing means comprises spring means interposed said drag blocks and said body member, respectively.
 10. The valve set forth in claim 7 wherein: said drag blocks each include an axially tapered outer surface formed thereon engageable with said well conduit for camming said drag blocks radially inwardly toward said valve body in response to urging said valve body into said well conduit.
 11. The valve set forth in claim 1 wherein: said drag member comprises a drag assembly including plural circumferentially spaced spring members supported on said body member and engageable with said wall of said well conduit upon insertion of said valve into said well conduit.
 12. The valve set forth in claim 11 wherein: said spring members comprise elongated cantilever spring fingers radially deflectable in response to engagement with said wall of said well conduit and operable to extend partially from an upper end of said well conduit in response to insertion of said valve into said well conduit.
 13. The valve set forth in claim 11 wherein: said spring members are mounted on a support collar adapted to be removably mounted on said body member.
 14. The valve set forth in claim 13 wherein: said collar includes opposed arcuate collar members joined together by a hinge and by a latch for mounting said collar on said body member and removing said collar from said body member, respectively.
 15. The valve set forth in claim 11 wherein: said spring members comprise elongated bow springs radially deflectable in response to engagement with said wall of said well conduit.
 16. The valve set forth in claim 15 wherein: said spring members are connected at one end to a first support collar adapted to be mounted on said body member and said spring members are connected at an opposite end to a second support collar mounted on another body member moveable relative to said body member and relative to an elongated mandrel connected to said closure member.
 17. The valve set forth in claim 16 wherein: said collars each comprise opposed collar members movable relative to each other for mounting and demounting said drag assembly with respect to said body members.
 18. The valve set forth in claim 1 including: an indicator member extending from said body member and operable to extend out of an upper end of said well conduit when said body member is disposed in said wall conduit.
 19. A mudsaver valve for use in well operations comprising: an elongated valve body member including an axial cylindrical bore therein; an elongated closure member disposed in said bore in said body member, said closure member including passage means opening to an outer surface of said closure member, said closure member being movable axially in said bore in said body member between valve open and closed positions; and a drag assembly connected to said body member and engageable with a wall of a well conduit upon insertion of said valve into said well conduit, said drag assembly including plural circumferentially spaced spring members supported on said body member and engageable with said wall of said well conduit for holding said body member substantially stationary with respect to said well conduit to permit opening and closing said valve by moving said closure member axially in said bore of said body member.
 20. The valve set forth in claim 19 wherein: said spring members comprise elongated cantilever spring fingers radially deflectable in response to engagement with said wall of said well conduit.
 21. The valve set forth in claim 20 wherein: said spring members are mounted on a support collar adapted to be removably mounted on said body member.
 22. The valve set forth in claim 21 wherein: said collar includes opposed arcuate collar members joined together by a hinge and a latch for mounting said collar on said body member and removing said collar from said body member, respectively.
 23. The valve set forth in claim 19 wherein: said spring members comprise elongated bow springs radially deflectable in response to engagement with said wall of said well conduit.
 24. The valve set forth in claim 23 wherein: said spring members are connected at one end to a first support collar adapted to be mounted on said body member and said spring members are connected at an opposite end to a second support collar mounted on another body member moveable relative to said body member and relative to an elongated mandrel connected to said closure member.
 25. The valve set forth in claim 24 wherein: said collars each comprise opposed collar members movable relative to each other for mounting and demounting said drag assembly with respect to said body members.
 26. The valve set forth in claim 19 including: spaced apart annular seal members mounted on said closure member and engageable with a borewall of said bore in said body member for preventing flow of fluid from said passage means in said closure member in the closed position of said closure member.
 27. The valve set forth in claim 26 including: a tapered bore part extending from one end of said body member and intersecting said bore in said body member for engaging said seals when said closure member moves from a valve open position to a valve closed position. 